blastular stage, when it still resembles
a hollow ball of cells. When half the blastula of a frog is amputated,
the remainder will develop not into half a frog but a smaller normal
frog; and if a human blastula is split by accident, the result will be
twins or even quadruplets. Thus the holons which at that earliest stage
behave as parts of the potentially whole organism manifest the same
self-regulating characteristics as the holons which at a lower (later)
level of the developmental hierarchy are parts of a potential organ; in
both cases (and throughout the intermediary stages) the holons obey the
rules laid down in their genetic code but retain sufficient freedom to
follow one or another developmental pathway, guided by the contingencies
of their environment.
These self-regulating properties of holons within the growing embryo
ensure that whatever accidental hazards arise during development,
the end-product will be according to norm. In view of the millions and
millions of cells which divide, differentiate, and move about, it must
be assumed that no two embryos, not even identical twins, are formed
in exactly the same way. The self-regulating mechanisms which correct
deviations from the norm and guarantee, so to speak, the end-result,
have been compared to the homeostatic feedback devices in the adult
organism -- so biologists speak of 'developmental homeostasis'.
The future individual is potentially predetermined in the chromosomes
of the fertilized egg; but to translate this blueprint into the finished
product, billions of specialized cells have to be fabricated and moulded
into an integrated structure. It would be absurd to assume that the genes
of that one fertilized egg should contain built-in provisions for each
and every particular contingency which every single one of its fifty-six
generations of daughter-cells might encounter in the process. However,
the problem becomes a little less baffling if we replace the concept of
the 'genetic blueprint', which implies a plan to be rigidly copied, by
the concept of a genetic canon of rules which are fixed, but leave room
for alternative choices, i.e., adaptive strategies guided by feedbacks
and pointers from the environment.
Needham once coined a phrase about 'the striving of the blastula to grow
into a chicken'. One might call the strategies by which it succeeds
the organism's 'pre-natal skills'. After all, the development of the
embryo and the subsequent maturation of the newborn into an adult are
continuous processes; and we must expect that pre-natal and post-natal
skills have certain basic principles in common with each other and with
other types of hierarchic processes.
The foregoing section was not intended to describe embryonic development,
only one aspect of it: the combination of fixed rules and variable
strategies, which we also found in instinctive skills (such as
nest-building, etc.) and learnt behaviour (such as language, etc.). It seems that life in all its manifestations, from morphogenesis to
symbolic thought, is governed by rules of the game which lend it order
and stability but also allow for flexibility; and that these rules,
whether innate or acquired, are represented in coded form on various
levels of the hierarchy, from the genetic code to the structures in the
nervous system associated with symbolic thought .
10
Ontogeny and phylogeny, the development of the individual and
the evolution of species, are the two grand hierarchies of
becoming. Phylogeny will be discussed in Part Three , but an anticipatory remark is
required in our present context of 'rules and strategies'.
Motor-car manufacturers take it for granted that it would make no sense
to design a new model from scratch; they make use of already existing
sub-assemblies -- engines, batteries, steering systems, etc. -- each of
which has been developed from long previous experience, and then proceed
by small modifications of some of these.
a hollow ball of cells. When half the blastula of a frog is amputated,
the remainder will develop not into half a frog but a smaller normal
frog; and if a human blastula is split by accident, the result will be
twins or even quadruplets. Thus the holons which at that earliest stage
behave as parts of the potentially whole organism manifest the same
self-regulating characteristics as the holons which at a lower (later)
level of the developmental hierarchy are parts of a potential organ; in
both cases (and throughout the intermediary stages) the holons obey the
rules laid down in their genetic code but retain sufficient freedom to
follow one or another developmental pathway, guided by the contingencies
of their environment.
These self-regulating properties of holons within the growing embryo
ensure that whatever accidental hazards arise during development,
the end-product will be according to norm. In view of the millions and
millions of cells which divide, differentiate, and move about, it must
be assumed that no two embryos, not even identical twins, are formed
in exactly the same way. The self-regulating mechanisms which correct
deviations from the norm and guarantee, so to speak, the end-result,
have been compared to the homeostatic feedback devices in the adult
organism -- so biologists speak of 'developmental homeostasis'.
The future individual is potentially predetermined in the chromosomes
of the fertilized egg; but to translate this blueprint into the finished
product, billions of specialized cells have to be fabricated and moulded
into an integrated structure. It would be absurd to assume that the genes
of that one fertilized egg should contain built-in provisions for each
and every particular contingency which every single one of its fifty-six
generations of daughter-cells might encounter in the process. However,
the problem becomes a little less baffling if we replace the concept of
the 'genetic blueprint', which implies a plan to be rigidly copied, by
the concept of a genetic canon of rules which are fixed, but leave room
for alternative choices, i.e., adaptive strategies guided by feedbacks
and pointers from the environment.
Needham once coined a phrase about 'the striving of the blastula to grow
into a chicken'. One might call the strategies by which it succeeds
the organism's 'pre-natal skills'. After all, the development of the
embryo and the subsequent maturation of the newborn into an adult are
continuous processes; and we must expect that pre-natal and post-natal
skills have certain basic principles in common with each other and with
other types of hierarchic processes.
The foregoing section was not intended to describe embryonic development,
only one aspect of it: the combination of fixed rules and variable
strategies, which we also found in instinctive skills (such as
nest-building, etc.) and learnt behaviour (such as language, etc.). It seems that life in all its manifestations, from morphogenesis to
symbolic thought, is governed by rules of the game which lend it order
and stability but also allow for flexibility; and that these rules,
whether innate or acquired, are represented in coded form on various
levels of the hierarchy, from the genetic code to the structures in the
nervous system associated with symbolic thought .
10
Ontogeny and phylogeny, the development of the individual and
the evolution of species, are the two grand hierarchies of
becoming. Phylogeny will be discussed in Part Three , but an anticipatory remark is
required in our present context of 'rules and strategies'.
Motor-car manufacturers take it for granted that it would make no sense
to design a new model from scratch; they make use of already existing
sub-assemblies -- engines, batteries, steering systems, etc. -- each of
which has been developed from long previous experience, and then proceed
by small modifications of some of these.
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